Island



(No Model.)

J. T. HBNTHORN.

ROOF GOVBRING.

No, 408,304. Patented Aug. 6,1889.

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UNITED STATES PATENT OEFIcE.

JOHN T. HENTHORN, OF PROVIDENCE, RHODE ISLAND.

ROOFi-COVERING'.

SPECIFICATION forming part of Letters Patent No. 408,304, dated August 6, 188:9. Application filed February 25, 1889. Serial No. 301,154. (No model.)

To all whom it may concern:

Be it known that I, JOHN T. I'IENTHORN, a citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new but more especially to iron roofs, so called,

used on iire-proof buildings. Roofs of this character are frequently used on the dynamohouses of electric-lighting stations, factories, engine-houses, dac.

A serious objection to a more general or extended use of metal-covered roofs is, I believe, due to the fact that the metal acts as a cooling-surface. In the sections of country eX- posed to wide variations in temperature as a result of climatic conditions, particularly during the winter-season, the metal covering or roof directly exposed to the outer air acts to cool the air within the building, thereby reducing its humidity and causing' the condensed moisture to collect on the under side of the roof, from which it drips tothe iioor below. Sometimes, in order to obviate the annoyance thus caused by the falling water, the rafters have been covered with wooden plank or boarding, between which and the outer metal coveringr millboard is interposed. lVhile such construction may, in a great degree, prevent the collection of condensed moisture it will not wholly do it, there being sufficient moisture produced upon the under side of the metal covering after awhile to permeate the interposed layer of paper and be absorbed into the wood, speedily causing it to decay. Another disadvantage to such woodenlined roof is that it is not iireproof from the interior of the building.

. The object I have in view is to produce a roof which is not only absolutely fire-proof bot-h from within and without, but at the same time one in which condensation is practically over- To that end my invention consists, essentially, of a composite roof composed of an outer covering` of metal, as corrugated iron, tin, dac., and an inner covering of non-conducting incombustible material, as ,asbestus Between these two may be interposed a layer or coating of tar, asphaltum, tarfpaper, or other equivalent material adapted to prevent the water or moisture formed directly upon the under surface of the metallic covering' from coming in contact with and saturating the asbestus lining', all as will be more fully hereinafter set forth and claimed.

In the appended drawings, Figure l is a perspective view of the upper portion of a building, showing a roof covered with corrugated iron according tofniy improvement. Fig. 2 is a transverse sectional View, enlarged, taken through the roof 5 and Fig. 8 is a plan view.

My invention may be described more in detail, as follows: I would state that the drawings represent the roof as supported on iron rafters a. It is obvious, however, that wooden beams or rafters may be employed, although such use of wood would, in a measure, militate against the roof as regards its noncombustible qualities. As before stated, I prefer to use iron rafters, they being supported by the walls of a building, as usual. To the rafters fore and aft metal purlins p are secured at proper intervals, also as common. The asbestus l), in the form of sheets more or less compressed, is supported by and in contact with the purlins. asbestus sheet-s sufficiently strong, they may be lined with wire gauze or netting having a comparatively line mesh. In the drawings I have represented abacking a, formed of wirenetting, which covers the entire roof. The same rests upon and is secured to the purlins. The asbestus board l), ot' suitable thickness, is next placed upon the wire-netting. The drawings show two layers. lVhen thus used, the seams or joints of the upper course break joints with the course below. In order to render the. roof perfectly impervious to moisture, I next cover the asbestus surface on top with one or more layers of tar-paper e, or other equivalent material, followed by a mopping of hot tar 1f. A similar coating of hot tar may be applied to the first course of the covering e, if desired, as indicated by the drawings.

In order to render the IOO Finally, the outer covering t' of metal is applied, and the Whole securely fastened together at suitable intervals by bolts m, which also pass through the purlins, as clearly shown. In engine-houses, dynamo-houses, &c., the metal covering il is usually made of corrugated iron, such form rendering the roof lighter, yet stronger and stiffer. An efficient joint ismade by lapping the sheets along the edges so as to engage two or three corrugations.

I make no claim, broadly, to a metallic roof, or even to a corrugated-iron roof supported directly upon the purlins, the essential features of my invention being the interposition of a surface of non-conducting inoombustible material between the purlins or roof-supports and the outer metallic covering.

I claim as my invention- .1. A composite roof composed of an inner lining or surface of non-conducting incombusvtible materials, of which asbestus forms the base thereof, purlins or other suitable sup- .ports therefor, and an outer covering of metal secured to said lining and purlins, substantially as described, and for the purpose specified.

2. A composite roof consisting of a corrugated-iron exterior surface, a surface of impervious material, as tar-paper, contiguous to the under side of the corrugated iron, an asbestus lining upon which the said impervious surface rests, a surface of Wire-netting to support the asbestus, and fixed purlins for supporting the Whole, and to which the several surfaces or layers are secured, substantiallyT as hereinbefore described.

3. The combination, with suitably-supported metallic purlins and an outer covering i of corrugated iron separated from said purlins, 

